Contact lenses provide a means for vision correction for a wide range of consumers. The advantages of contact lens wear are numerous. Improved convenience and improved appearance in comparison to spectacle glasses are probably the two most important advantages to most consumers. However, contact lenses require stringent care regimes in order to ensure comfort and avoid ocular infections. Proper care of contact lenses typically requires the consumer to periodically clean and disinfect the lenses, to prevent infection or other deleterious effects on ocular health which may be associated with contact lens wear.
In recent years, multiple-purpose solutions, which clean, disinfect, and rinse contact lenses all without mechanically rubbing lenses, have been developed as a new type of lens care systems. These new systems start dominating the most of the lens care market. Such popularity is most likely derived from the easiness and convenience provided by these new systems to consumers. In order to achieve a satisfactorily disinfecting result, a contact lens has to be in a MPS solution for a sufficient time period. However, consumers do not have a direct way to determine if their lenses have been in the lens care solution long enough to disinfect the lenses. It would be desirable to provide customers means by which they could visually identify when their lenses are clean and ready to wear.
Therefore, there exists a need for a lens care kit capable of discoloring or changing color over the time period required for disinfection of contact lenses.